我已经编写了一系列两个相关的case语句（x4场景），由于原始数据的设置方式，我得到了每个惟一id的两个重复行。我将为ladder\u name和ladder\u value列生成一个单独的行，而实际上它们是相互关联的，只应组合生成。
我不知道如何调整case语句，使每个惟一id只能得到一行。
代码：

SELECT 
    # overall 
        sc.salesforce_id,
    # first trigger
        member_id_lh1, 
        ladder_config_id_lh1, 
        trigger_name_lh1,
        trigger_record_id_lh1, 
        date_trigger_event_lh1,
        ladder_name_lh1,
        ladder_value_lh1,
        ladder_change_lh1,
    # second trigger 
        member_id_lh2, 
        trigger_name_lh2,
        trigger_record_id_lh2, 
        date_trigger_event_lh2,
        ladder_name_lh2,
        ladder_value_lh2,
        ladder_change_lh2,
        days_spent,
        rank,
    # regions
        #placeholder for now 
    #demographics
        ar.`name` as alumni_region_name,
        gender,
        is_parent,
        is_teacher,
        first_generation_american,
        first_generation_college_going,
        lgbtq,
        veteran,
        person_of_color,
        low_income_background,
        registered_to_vote,
        contact_in_ri_supported_region,
        ethnicity,
    # current ladder level
        ladder_engagement as current_engagement_level,
        ladder_advocacy as current_advocacy_level,
        ladder_elected as current_elected_level,
        ladder_policy as current_policy_level,
        ladder_organizing as current_organizing_level,
        ladder_collective as current_collective_level,
    # Count - gain and loss
        case 
            when (ladder_value_lh2 > ladder_value_lh1 and ladder_value_lh2 is not null) then 1
                else -1 
            end as moved_up_down,
    #referring ladder level
        case 
            when ladder_value_lh2 > ladder_value_lh1 and ladder_value_lh2 is not null then ladder_name_lh2 
                else ladder_name_lh1 
            end as gain_moved_to_from_ladder_name,
        case 
            when ladder_value_lh2 > ladder_value_lh1 and ladder_value_lh2 is not null then ladder_value_lh2 
                else ladder_value_lh1 
            end as gain_moved_to_from_ladder_level,
        case 
            when ladder_value_lh2 < ladder_value_lh1 and ladder_value_lh2 is not null then ladder_name_lh2 
                else ladder_name_lh1 
            end as loss_moved_to_from_ladder_name, 
        case 
            when ladder_value_lh2 < ladder_value_lh1 and ladder_value_lh2 is not null then ladder_value_lh2 
                else ladder_value_lh1 
            end as loss_moved_to_from_ladder_level, 
    #referring trigger level 
        case 
            when ladder_value_lh2 > ladder_value_lh1 and ladder_value_lh2 is not null then trigger_name_lh2 
                else trigger_name_lh1 
            end as gain_moved_to_from_trigger_name,
        case 
            when ladder_value_lh2 > ladder_value_lh1 and ladder_value_lh2 is not null then ladder_value_lh2 
                else ladder_value_lh1 
            end as gain_moved_to_from_trigger_level,
        case 
            when ladder_value_lh2 < ladder_value_lh1 and ladder_value_lh2 is not null then trigger_name_lh2 
                else trigger_name_lh1 
            end as loss_moved_to_from_trigger_name, 
        case 
            when ladder_value_lh2 < ladder_value_lh1 and ladder_value_lh2 is not null then ladder_value_lh2 
                else ladder_value_lh1 
            end as loss_moved_to_from_trigger_level

    from leeds_new.salesforce_contacts as sc
        inner join cte_ladder_history_join_lh1_lh2_current_trigger_record on sc.salesforce_id = cte_ladder_history_join_lh1_lh2_current_trigger_record.member_id_lh1
        inner join leeds_new.salesforce_alumni_regions_federated as ar on sc.alumni_region_id = ar.alumni_region_id;

结果：